TY - JOUR A1 - Klemm, Juliane A1 - Herzschuh, Ulrike A1 - Pisaric, Michael F. J. A1 - Telford, Richard J. A1 - Heim, Birgit A1 - Pestryakova, Luidmila Agafyevna T1 - A pollen-climate transfer function from the tundra and taiga vegetation in Arctic Siberia and its applicability to a Holocene record JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - This study aims to establish, evaluate, and apply a modern pollen-climate transfer function from the transition zone between arctic tundra and light-needled taiga in Arctic Siberia. Lacustrine samples (n = 96) from the northern Siberian lowlands of Yakutia were collected along four north-to-south transects crossing the arctic forest line. Samples span a broad temperature and precipitation gradient (mean July temperature, T-July: 7.5-18.7 degrees C; mean annual precipitation, P-ann: 114-315 mm/yr). Redundancy analyses are used to examine the relationship between the modern pollen signal and corresponding vegetation types and climate. Performance of transfer functions for T-July and P-ann were cross-validated and tested for spatial autocorrelation effects. The root mean square errors of prediction are 1.67 degrees C for T-July and 40 mm/yr for P-ann. A climate reconstruction based on fossil pollen spectra from a Siberian Arctic lake sediment core spanning the Holocene yielded cold conditions for the Late Glacial (1-2 degrees C below present T-July). Warm and moist conditions were reconstructed for the early to mid Holocene (2 degrees C higher T-July than present), and climate conditions similar to modern ones were reconstructed for the last 4000 years. In conclusion, our modern pollen data set fills the gap of existing regional calibration sets with regard to the underrepresented Siberian tundra-taiga transition zone. The Holocene climate reconstruction indicates that the temperature deviation from modern values was only moderate despite the assumed Arctic sensitivity to present climate change. KW - Mean July temperature KW - Reconstruction KW - Weighted-average partial least squares KW - Autocorrelation KW - Yakutia Y1 - 2013 U6 - https://doi.org/10.1016/j.palaeo.2013.06.033 SN - 0031-0182 SN - 1872-616X VL - 386 SP - 702 EP - 713 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Biskaborn, Boris K. A1 - Subetto, D. A. A1 - Savelieva, L. A. A1 - Vakhrameeva, P. S. A1 - Hansche, A. A1 - Herzschuh, Ulrike A1 - Klemm, J. A1 - Heinecke, L. A1 - Pestryakova, Luidmila Agafyevna A1 - Meyer, H. A1 - Kuhn, G. A1 - Diekmann, Bernhard T1 - Late Quaternary vegetation and lake system dynamics in north-eastern Siberia: Implications for seasonal climate variability JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - Although the climate development over the Holocene in the Northern Hemisphere is well known, palaeolimnological climate reconstructions reveal spatiotemporal variability in northern Eurasia. Here we present a multi-proxy study from north-eastern Siberia combining sediment geochemistry, and diatom and pollen data from lake-sediment cores covering the last 38,000 cal. years. Our results show major changes in pyrite content and fragilarioid diatom species distributions, indicating prolonged seasonal lake-ice cover between similar to 13,500 and similar to 8900 cal. years BP and possibly during the 8200 cal. years BP cold event. A pollen-based climate reconstruction generated a mean July temperature of 17.8 degrees C during the Holocene Thermal Maximum (HTM) between similar to 8900 and similar to 4500 cal. years BP. Naviculoid diatoms appear in the late Holocene indicating a shortening of the seasonal ice cover that continues today. Our results reveal a strong correlation between the applied terrestrial and aquatic indicators and natural seasonal climate dynamics in the Holocene. Planktonic diatoms show a strong response to changes in the lake ecosystem due to recent climate warming in the Anthropocene. We assess other palaeolimnological studies to infer the spatiotemporal pattern of the HTM and affirm that the timing of its onset, a difference of up to 3000 years from north to south, can be well explained by climatic teleconnections. The westerlies brought cold air to this part of Siberia until the Laurentide ice sheet vanished 7000 years ago. The apparent delayed ending of the HTM in the central Siberian record can be ascribed to the exceedance of ecological thresholds trailing behind increases in winter temperatures and decreases in contrast in insolation between seasons during the mid to late Holocene as well as lacking differentiation between summer and winter trends in paleolimnological reconstructions. (C) 2015 Elsevier Ltd. All rights reserved. KW - Diatoms KW - Pollen KW - Summer and winter temperature KW - Holocene Thermal Maximum KW - Aquatic and terrestrial ecosystems KW - Lake-ice cover Y1 - 2016 U6 - https://doi.org/10.1016/j.quascirev.2015.08.014 SN - 0277-3791 VL - 147 SP - 406 EP - 421 PB - Elsevier CY - Oxford ER -